N-Donor ligand activation of titanocene for the Biginelli reaction via the imine mechanism

The remarkable activation of stable titanocene dichloride (Cp₂TiCl₂) was achieved using N-donor ligand urea in an alcoholic solvent, leading to the formation of a Ti(iv) species [(MeO)₂Ti(NHCONH₂)]⁺, the existence of which was verified by ESI-MS, ESI-MS/MS, and NMR. Catalyzed by the newly formed Ti(iv) species, a myriad of 3,4-dihydropyrimidin-2-(1H)-ones were produced via a three-component Biginelli reaction. Further mechanistic investigation indicated that the Biginelli reaction had taken place via the imine route.

Stable titanocene dichloride (Cp₂TiCl₂) was activated by the N-donor ligand urea to form [(MeO)₂Ti(NHCONH₂)]⁺, which catalyzed the Biginelli reaction to produce 3,4-dihydropyrimidin-2-(1H)-ones.

Triple zirconocene/brønsted acid/CuO cooperative and relay catalysis system for tandem Mannich addition/C–C formative cyclization/oxidation

Triple zirconocene/brønsted acid/CuO cooperative and relay catalysis system for tandem Mannich addition/C–C formative cyclization/oxidation.

Ethanol promoted titanocene Lewis acid catalyzed synthesis of quinazoline derivatives

An efficient strategy to activate air-stable Lewis acid precursor Cp₂TiCl₂ with alcoholic solvent for the rapid synthesis of quinazoline derivatives.

Titanocene dichloride and poly(o-aminophenol) as a new heterogeneous cooperative catalysis system for three-component Mannich reaction

A heterogeneous binary acid system featuring an organometallic precusor, titanocene dichloride, and poly(o-aminophenol) as a cooperative Brønsted acid supporter was developed.